The invention relates to a controller for hot swapping of an extended I/O (input-output) device to a computer body, and more particularly to a controller for hot swapping which can realize connection of an extended I/O device to a computer body without relying upon any software when the computer body is in operation.
In conventional small-sized portable computers, there are computer systems that, for reasons of the restriction of space for mounting on the body side, small frequency of use and the like, use extended I/O devices, called xe2x80x9cport barsxe2x80x9d or xe2x80x9cdocking stations,xe2x80x9d for connecting I/O ports, such as serial ports and parallel ports, floppy disk drive units and the like.
Conventional controllers for hot swapping of an extended I/O device to a computer body are disclosed, for example, in Japanese Patent Laid-Open No. 9712,/1997. This computer system has an extended I/O device, such as a docking station or a card dock, that is detachably mounted on the computer body. The extended I/O device is connected to the computer body through a docking connector. An I/O controller contained in the computer body detects docking and controls the extended I/O device.
This conventional controller for hot swapping of an extended I/O device to a computer body will be explained in more detail.
The conventional controller for hot swapping comprises a computer body and an extended I/O device. The computer body comprises: an I/O controller for controlling various I/O units and ports; a connector connected to the I/O controller through a plurality of data lines; a system controller connected to the I/O controller through a system bus; and CPU connected to the system controller through a CPU bus, for executing softwares. The extended I/O device comprises: a connector; a hard disk drive unit, a floppy disk drive unit, and output ports connected to the connector; a data line for connecting the hard disk drive unit to the extension connector; a data line for connecting the floppy disk drive unit to the extension connector; and data lines for connecting I/O ports to the extension connector.
According to the conventional controller for hot swapping of an extended I/O device to the computer body, as soon as the connection of the connector in the computer body to the connector in the extended I/O device is confirmed a connection signal is output from the I/O controller to the extended I/O device. Based on the input of the connection signal, the hard disk drive unit, the floppy disk drive unit, and the I/O ports are controlled, thus permitting the hard disk drive unit, the floppy disk drive unit, and the I/O ports to be used as extended devices for the computer body.
Another conventional controller for hot swapping of an extended I/O device to a computer body will be explained. This conventional controller for hot swapping include an I/O controller provided in an extended I/O device, and connectors for connecting a system bus in a computer body to the I/O controller. The other construction is the same as that described in the above computer system. According to this computer system, the connector in the computer body is connected to the connector in the extended I/O device to connect the I/O controller provided in the extended I/O device to the system bus in the computer body.
According to the conventional controllers for hot swapping of an extended I/O device to a computer body, the provision of the I/O controller in the computer body necessitates a large number of signals for the connection of the extended I/O device to the computer body, leading to an increase in the number pins for the connectors and an increased size of the connectors and, in its turn, an increased size of the computer body. On the other hand, the provision of the I/O controller in the extended I/O device necessitates a special software having initialization data for the I/O controller in order to enable hot swapping. This limits the kind of softwares that can use the extended I/O device.
Accordingly, it is an object of the invention to provide a controller for hot swapping of an extended I/O device to a computer body that can reduce the number of signals required at the time of connection of the computer body to the extended I/O device and can realize hot swapping without relying upon any special software.
According to the first feature of the invention, an apparatus comprises: a computer body including a processing unit and a first I/O (input-output) controller having a first register for containing predetermined data in a predetermined address; and an extended I/O device which is hot swappable to the computer body and comprises a second I/O controller having a second register, said second register having an address corresponding to the predetermined address of the first register,
said apparatus further comprising control means for detecting, upon providing power to the computer body, connection of the I/O device to the computer body, and for controlling the initialization of the first and second I/O controllers based on the detection results.
Preferably, when the detection results indicate that the extended I/O device is not connected to the computer body, upon providing power to the computer body, the first I/O controller is initialized; and, after initialization of the first I/O controller, upon connection of the extended I/O device to the computer body, said control means copies initialization data in the set register in the first I/O controller into the register in the second I/O controller. On the other hand, preferably, when the detection results indicate that the extended I/O device is already in connection to the computer body upon providing power to the computer body, said control means initializes the register in the second I/O controller instead of the set register in the first I/O controller. Preferably, the address of the register in the second I/O controller is identical to the predetermined address of the set register in the first I/O controller. The control means may receive a swapping signal from a connector for connecting the extended I/O device to the computer body. A system controller may be included in the computer body. Preferably, upon connection of the extended I/O device to the computer body, the control means instead of the system controller controls the first and second I/O controllers.